Marvel 'chipping' as its been explained to me was caused by dull paper cutters during the triming of the comics in the production process. This photo does not look like that to me. It looks like it may be damage from tape, if all the color is pulled off the cover. Are there old peices of tape on that book? Amateur tape repairs can bring the grade of a comic 1 full point or more, depending on the extent. If what's shown in the photo is the only major damage, I'd say it would impact the grade between 0.5 and 1.0 point.